U.S. Pat. No. 2,380,437 discloses a crutch assembly which includes a crutch and a foldable seat. One problem with the crutch assembly is that when the seat is in its folded position, a mechanism for supporting the seat, such as supporting legs, etc., is not compactly folded and is exposed to the user, so that the user may easily get hurt by the folded supporting mechanism. U.S. Pat. No. 3,999,565 discloses a walking stick device in which a support member for supporting the wounded knee or leg is fastened to a standard/body in a retractable fashion. The walking stick device may encounter the similar problem.